ASTM_D_1832_-_04_2009.pdf

Designation:D1832 04(Reapproved 2009)TAPPI Method T 659 wd-85Standard Test Method forPeroxide Number of Petroleum Wax1This standard is issued under the fixed designation D1832;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the perox-ide number of petroleum wax.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Terminology2.1 Definitions:2.1.1 peroxide numberthe milliequivalents of constituentsper 1000 g of wax that will oxidize potassium iodide.3.Summary of Test Method3.1 A quantity of sample is dissolved in xylenes andacidified with acetic acid solution.A solution of potassiumiodide is added and,after a reaction period,the solution istitrated with sodium thiosulfate solution to the end pointindicated by the color change of added starch solution.4.Significance and Use4.1 The magnitude of the peroxide number is an indicationof the quantity of oxidizing constituents present.Deteriorationof petroleum wax results in the formation of peroxides andother oxygen-carrying compounds.The peroxide number mea-sures those compounds that will oxidize potassium iodide.5.Apparatus5.1 Iodine Flask,borosilicate glass,250-mL capacity,glass-stoppered.6.Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.2Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean distilled water or water ofequal purity.6.3 Acetic Acid SolutionMix 4 mL of concentrated hydro-chloric acid(HCl,sp gr 1.19)with 996 mL of ACS specialreagent grade glacial acetic acid(CH3CO2H).The acetic acidmust pass the12-h test for substances reducing K2Cr2O7.6.4 Xylenes,(WarningFlammable liquid.Vapor harm-ful.)Treated to remove oxidizing impurities.One way to dothis is to pass the xylenes through an activated alumina columnshortly prior to use.6.5 Potassium Dichromate,Standard Solution(0.1 N)Recrystallize potassium dichromate(K2Cr2O7)twice from anaqueous solution and dry at about 325F(164C)to constantweight.Dissolve 2.452 g of the purified K2Cr2O7in water anddilute to 500 mL in a volumetric flask.6.6 Potassium Dichromate,Standard Solution(0.01 N)Dilute 100 mL of 0.1 N K2Cr2O7solution with water to 1000mL in a volumetric flask.6.7 Potassium Iodide SolutionDissolve 120 g of potas-sium iodide(KI)in 100 mL of water.Discharge any color fromthis solution as follows:put 1 mL of KI solution,50 mL ofwater,and 5 mL of starch solution in a 300-mL flask andblanket with nitrogen or carbon dioxide.If a blue colordevelops,add 0.005 N Na2S2O3solution from a microburet1This test method is under the jurisdiction of the ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.10.0A on Physical/Chemical Properties.Current edition approved Oct.1,2009.Published November 2009.Originallyapproved in 1961.Last previous edition approved in 2004 as D183204.DOI:10.1520/D1832-04R09.2Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For Suggestions on the testing of reagents notlisted by the American Chemical Society,see Annual Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.until color just disappears.Calculate and add sufficientNa2S2O3solution to the main KI solution to convert all freeiodine to iodide.When starch solution is added to 1 mL of KIsolution a blue color should not develop,but upon the additionof 1 drop of 0.01 N K2Cr2O7solution and 2 drops ofconcentrated hydrochloric acid(HCl,sp gr 1.19),a blue colorshould develop.Store this solution under chloroform by addinga few millilitres to the surface of the liquid.6.8 Sodium Thiosulfate,Standard Solution(0.1 N)Dissolve 12.5 g of sodi